This blog post is part of the "Tech Talk" series focused on the First Responder Network Authority’s (FirstNet Authority) standards development activities to support public safety. This post recaps discussions linked to public safety and other related topics from the 3GPP Plenary meetings that were conducted online March 16-20, 2020. The FirstNet Authority represented public safety interests at the Plenary meetings.

Highlights

After holding face-to-face meetings in January, the three 3GPP Technical Specification Group (TSG) Chairs announced that all Service and Systems Aspects (SA), Radio Access Network (RAN), and Core Network and Terminals (CT) working group meetings scheduled for the remainder of Quarter 1 (Q1) have been converted into electronic meetings (e-meetings) using email and teleconferencing. More recently, 3GPP has announced that all face-to-face meetings scheduled through August have been converted to e-meetings. Despite the challenges for our colleagues working around the globe in different time zones, the chairs and delegates are working hard to move the standards forward as much as possible.

As you may recall, our last blog covering the December 2019 3GPP Plenary meetings reported that final work scope determination for 3GPP Release 17 (R17) was completed. Although the situation seems to change almost daily, the following decisions have currently been made:

• 3GPP Release 16 (R16) feature completion date has been moved from March 2020 to June 2020.
• The R17 timeline will be delayed three months to September 2021.
• The R17 feature content agreed upon in the December meetings remains in place and unchanged.

The following information provides details on each of the March Plenary e-meetings with a focus on public safety activities. As usual, the 3GPP meetings were represented by nearly all major mobile equipment vendors, chip manufacturers, software vendors, and network operators from about 35 countries. In addition, the FirstNet Authority and other government agencies representing public safety interests were in attendance.

The Radio Access Network Plenary

The RAN TSG is responsible for defining the functions, requirements and interfaces of the 3GPP radio network. The RAN Plenary e-meeting included slightly over 300 delegates. 

The RAN Plenary e-meeting focused primarily on the continuation and completion of Release 16 topics.

Since work was not able to progress in the e-meetings as fast as in the regular face-to-face meetings, the R16 stage 3 freeze date is moved to June 2020 from March 2020. The 3GPP R16 RAN features of interest to public safety that are mostly complete include: 5G radio-based access to unlicensed spectrum to increase data throughput, 5G V2X (Vehicle-to-everything) with NR (New Radio) sidelink for device to device (D2D) communications for out of coverage scenarios, mobile power savings for first responder pedestrian battery life improvements, and 5G radio positioning support using broadcasting network assistance data for vertical location calculations by a mobile device.

Several contributions were submitted to discuss the creation of standardized sets of R16 5G User Equipment (UE) radio features and capabilities. However, due to lack of an agreement among manufacturers and operators on those features, the discussion will continue in the April 2020 RAN working group e-meetings.

The Service and Systems Aspects Plenary

The SA TSG is responsible for the overall architecture and service capabilities of 3GPP based systems. The SA Plenary meeting included approximately 160 delegates. The SA Plenary limited the scope of its e-meeting to focus on Release 16, as well as any discussions regarding the scope of existing work items or new work items.

Minimal progress was reported on R17 work including some of the key features for public safety such as 5G Multicast-Broadcast services (5MBS) and 5G Proximity services (ProSe) because of the SA WG2 focus on progressing R16 work items. A long e-discussion took place concerning an ambiguity about the inclusion of service continuity for the ProSe UE-Network relay in R17. Service continuity would attempt to keep communications going when a user's device loses radio contact with the network and creates a path to the network through a relay device. The FirstNet Authority presented its position that such capability is desirable for public safety and should be included in R17. SA did not conclude on this issue and directed SA2 to discuss it further and to reach an agreement prior to the next SA Plenary e-meeting in June.

Limited progress was made on the remaining backlogged security work items. No security study items were addressed. FirstNet Authority had expressed support during the SA WG3 meeting for the inclusion of mandatory User Plane Integrity Protection (UPIP) from R16 onwards. Integrity protection prevents data from being modified in an unauthorized or undetected manner. While mandatory integrity protection has been a feature of the 3GPP network signaling plane from the start of LTE, this would be a new security improvement for the network’s user data plane in 5G. SA directed SA3 to include evaluation of mandatory UPIP in their upcoming April e-meeting. Of course, these security features are below the mission critical applications that support both confidentiality and integrity of all signaling and data.

In other news, the study on “Mission Critical services over 5G multicast-broadcast system” was completed along with a number of corrections and enhancements to the Mission Critical Data (MCData) specifications. The 5G system currently does not have a broadcast capability equivalent to 4G LTE Multimedia Broadcast Multicast Services (MBMS) and the study looked at deficiencies in the 4G MBMS capability for public safety that might be overcome in 5G. In addition, a new work item titled “Enhanced Mission Critical Push-to-talk architecture phase 3” was approved to continue development of Mission Critical PTT features such as enhanced location services, discreet listening and logging. Enhanced location services includes items important to address for public safety including location from multiple clients (e.g. phone and tablet) and location from an unauthenticated user. Discreet listening is an important public safety dispatch feature and logging/recording is critically important for mission critical systems.

The Core Network and Terminals Plenary

The CT work covers the protocol details and follows the requirements and architectural work performed in the SA working groups. The CT Plenary e-meeting included 90 participants. The primary focus was on approval of R16 work. A technical vote may be required to make a final selection of protocol for at least one R16 feature.

At this meeting, the FirstNet Authority achieved a major milestone with the approval of the technical specification (TS 29.582) for LMR-interworking with MCData on 4G (LTE) systems. This specification provides the standards for the 3GPP MCData side of interworking with legacy LMR systems for the Short Data Service (SDS). In our December blog, we noted that the LMR-interworking for MCPTT specifications (TS 29.379, TS 29.380) had been approved. With the addition of LMR-interworking for MCData, all basic LMR-interworking specifications have now been approved. Work continues in the Alliance for Telecommunications Industry Solutions (ATIS) and Telecommunications Industry Association (TIA) on the LMR side of the interworking effort. Additional features will continue to be added to LMR interworking in R17. R17 efforts will also begin the work to ensure that MCPTT, MCVideo and MCData will operate over 5G systems.

5G R16 work made significant progress at this e-Plenary meeting but has not reached the completion rate it might have if meetings had been face-to-face. The 3GPP created a list of feature items that still need completion on “exception sheets.”  These exception sheets were endorsed for continued work in the CT working groups until June when the end of R16 is now scheduled.

The FirstNet Authority’s Standards Team, along with the AT&T Standards Team, will be participating in the development of specifications for the study and work items for R17 over the coming months. 

Further information on the 3GPP’s work and organization can be found at: www.3gpp.org.